package com.example.demo.controller;

import cn.hutool.core.io.FileUtil;
import cn.hutool.core.util.IdUtil;
import cn.hutool.core.util.StrUtil;
import com.example.demo.common.Result;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;

@RestController
@RequestMapping("/files")
public class FileController {

    @Value("${server.port}")
    private  String port;

    @Value("${file.ip}")
    private String ip;

    /**
     * 上传接口
     * @param file
     * @return
     * @throws IOException
     */
    @PostMapping("/upload")
    public Result<?> upload(MultipartFile file) throws IOException {
        String originalFilename = file.getOriginalFilename(); //获取源文件名称
        String flag = IdUtil.fastSimpleUUID();//定义文件的唯一标识（前缀）,解决相同文件名覆盖问题
        String rootFilePath = System.getProperty("user.dir") + "/src/main/resources/files/" + flag + "_" + originalFilename; //获取文件上传路径
        FileUtil.writeBytes(file.getBytes(),rootFilePath); //把文件写入上传路径
        return Result.success(ip+":"+port+"/files/"+flag); //返回结果url
    }

    /**
     * 下载接口
     * @param response
     * @param flag
     * @return
     */
    @GetMapping("/{flag}")
    public void getFiles(HttpServletResponse response, @PathVariable String flag){
        OutputStream os; //新建一个输出流对象
        String basePath = System.getProperty("user.dir") + "/src/main/resources/files/"; //定于文件上传的根路径
        List<String> fileNames = FileUtil.listFileNames(basePath); //获取所有的文件名称
        String fileName = fileNames.stream().filter(name -> name.contains(flag)).findAny().orElse("");//找到和参数一致的文件
        try {
            if (StrUtil.isNotEmpty(fileName)) {
                response.addHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(fileName,"UTF-8"));
                response.setContentType("application/octet-stream");
                byte[] bytes = FileUtil.readBytes(basePath + fileName); //通过文件的路径读取文件字节流
                os = response.getOutputStream();//通过输出流返回文件
                os.write(bytes);
                os.flush();
                os.close();
            }
        } catch (Exception e) {
            System.out.println("文件下载失败");
        }
    }
}
